Display device and method of manufacturing the same

ABSTRACT

A display device including: a plastic window including a light transmittance film and a polymer layer, and a functional film including a touch screen panel film, a polarizing film, or a combination thereof. The light transmittance film, the polymer layer, and the functional film are sequentially stacked on each other, and the light transmittance film, the functional film, and the polymer layer are attached to each other by a plastic. A method of manufacturing the same is also provided.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.14/455,863, filed Aug. 8, 2014, which claims priority to and the benefitof Korean Patent Application No. 10-2014-0036220, filed Mar. 27, 2014,the entire content of both of which is incorporated herein by reference.

BACKGROUND 1. Field

Aspects of embodiments of the present invention are directed toward adisplay device and a method of manufacturing the same.

2. Description of the Related Art

Currently known display devices include, for example, a liquid crystaldisplay (LCD), a plasma display panel (PDP), an organic light emittingdiode (OLED) display, a field effect display (FED), an electrophoreticdisplay device, and the like.

Such display devices generally include a display module for displayingan image and a window protecting the display module.

The window may be made of glass. However, because the glass may beeasily broken by an external impact, a window made of glass may beeasily damaged when applied to a portable device, such as a mobilephone. Therefore, a window made of a plastic instead of glass has beenrecently researched. The plastic window has excellent flexibility and,thus, may be applied to a flexible display device.

The plastic window may be assembled by using an adhesive layer appliedto a panel, such as a display panel, a touch screen panel, and/or apolarizing plate. However, the adhesive layer increases a thickness of adisplay device and prolongs a manufacturing time due to an adhesionprocess. In addition, the plastic window may be bent during themanufacturing process and may have unsatisfactory effects on a shape andreliability of the display device.

SUMMARY

An embodiment of the present invention provides a display deviceincluding a plastic window.

Another embodiment provides a method of manufacturing the displaydevice.

According to one embodiment, a display device includes a plastic windowincluding a light transmittance film and a polymer layer and afunctional film including a touch screen panel film, a polarizing film,or a combination thereof. The light transmittance film, the polymerlayer, and the functional film are sequentially stacked on each otherand are attached to one another by a plastic.

The light transmittance film and the polymer layer may be bonded to eachother without an adhesive therebetween, and the functional film and thepolymer layer may be bonded to each other without an adhesivetherebetween.

The display device may be manufactured by inserting the lighttransmittance film and the functional film in a film insert manner andthen injecting a molten polymer between the light transmittance film andthe functional film and compressing the light transmittance film and thefunctional film.

The light transmittance film may include a plastic substrate selectedfrom among a polyethyleneterephthalate (PET) film, a polycarbonate (PC)film, a polymethylmethacrylate (PMMA) film, apolycarbonate/polymethylmethacrylate (PC/PMMA) film, a combinationthereof, or a two or more layer stack thereof.

The light transmittance film may further include a binder layer betweenthe plastic substrate and the polymer layer.

The light transmittance film may include a hard coating layer at a sideof the plastic substrate.

The polymer layer may include polycarbonate (PC), apolycarbonate-polymethylmethacrylate (PC-PMMA) blend, a cycloolefinpolymer (COP), a copolymer thereof, a combination thereof, or a two ormore layer stack thereof.

The display device may further include a display panel at a side of thefunctional film.

The display panel may be a liquid crystal display panel or an organiclight emitting display panel.

The display device may further include an adhesive layer between thefunctional film and the display panel.

According to another embodiment, a method of manufacturing a displaydevice includes preparing a light transmittance film, preparing afunctional film including a touch screen panel film, a polarizing film,or a combination thereof, placing the light transmittance film and thefunctional film in a mold, injecting a molten polymer between the lighttransmittance film, and compressing the light transmittance film and thefunctional film to mold the polymer.

The preparing the light transmittance film may include forming a hardcoating layer on one surface of a plastic substrate.

The plastic substrate may be selected from among apolyethyleneterephthalate (PET) film, a polycarbonate (PC) film, apolymethylmethacrylate (PMMA) film, apolycarbonate/polymethylmethacrylate (PC/PMMA) film, a combinationthereof, or a two or more layer stack thereof.

The preparing the functional film may include preparing a touch screenpanel film, a polarizing film, or a combination thereof, and attaching adisplay panel on one side of the touch screen panel film, the polarizingfilm, or the combination thereof.

The polymer may have a melt flow index (MFR) in a range of about 30 g/10min to about 80 g/10 min with a reference to about 300° C.

The polymer may include polycarbonate (PC), apolycarbonate-polymethylmethacrylate (PC-PMMA) blend, a cycloolefinpolymer (COP), a copolymer thereof, or a combination thereof.

The plastic window-functional film assembly obtained in a dual-filminsert manner may be closely attached to (e.g., closely adhered to) eachother without a separate adhesive layer and, thus, may reduce or preventa thickness increase due to the adhesive layer and may be manufacturedusing a simple process by omitting the adhesive layer (e.g., by omittingattachment of the adhesive layer). In addition, the plastic window maybe prevented from being bent (e.g., permanently bent or curved) becausethe plastic window-functional film assembly prevents an asymmetricstress from being distributed in a thickness direction and maintains asymmetric stress when the molten polymer is quickly (e.g., sharply)cooled down by disposing the light transmittance film and the functionalfilm on opposite sides of the molten polymer during the injectionmolding. Accordingly, the display device may be prevented from beingbent and, thus, may increase reliability of a product.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a display device according toone embodiment,

FIGS. 2 to 4 are schematic views sequentially showing a method ofmanufacturing the display device according to one embodiment,

FIG. 5 is a schematic view showing a plastic window-functional filmassembly obtained in a dual-film insert manner according to oneembodiment,

FIG. 6 is a schematic view showing symmetric stress distribution of theplastic window-functional film assembly obtained in the dual-film insertmanner according to one embodiment,

FIGS. 7 to 9 are schematic views sequentially showing a method ofmanufacturing the display device according to another embodiment,

FIG. 10 is a graph showing high temperature reliability evaluation ofthe plastic window-functional film assembly obtained in the dual-filminsert manner according to the embodiment,

FIG. 11 is a graph showing high temperature reliability evaluation of aplastic window obtained in a comparative (e.g., general) film insertmanner,

FIG. 12 is a graph showing high temperature/humidity reliabilityevaluation of the plastic window-functional film assembly obtained inthe dual-film insert manner according to the embodiment,

FIG. 13 is a graph showing high temperature/humidity reliabilityevaluation of the plastic window obtained in the comparative film insertmanner, and

FIG. 14 is a cross-sectional view showing a display device according toone embodiment.

DETAILED DESCRIPTION

This disclosure will be described more fully hereinafter in thefollowing detailed description, in which some but not all embodiments ofthis disclosure are described. This disclosure may be embodied in manydifferent forms and is not construed as limited to the exampleembodiments set forth herein.

In the drawings, the thickness of layers, films, panels, regions, etc.,may be exaggerated for clarity. Like reference numerals designate likeelements throughout the specification. It will be understood that whenan element, such as a layer, film, region, or substrate, is referred toas being “on” another element, it can be directly on the other elementor intervening elements may also be present. When an element is referredto as being “directly on” another element, there are no interveningelements present. Further, when a first element is being described as“coupled” or “connected” to a second element, the first element may bedirectly coupled or connected to the second element or may be indirectlycoupled or connected to the second element via one or more interveningelements. Even further, the use of “may” when referring to embodimentsof the present invention relates to “one or more embodiments of thepresent invention.”

Hereinafter, a display device according to one embodiment is illustratedwith reference to FIG. 1.

FIG. 1 is a cross-sectional view showing a display device according toone embodiment.

The display device according to one embodiment includes a plastic window300, a functional film 200, and a display panel 100.

The plastic window 300 includes a light transmittance film 320 and apolymer layer 310.

The light transmittance film 320 includes a plastic substrate 320 q, abinder layer 320 p, and a hard coating layer 320 r.

The plastic substrate 320 q may be a substrate used for a film insertforming process and may be, for example, a polyethyleneterephthalate(PET) film, a polycarbonate (PC) film, a polymethylmethacrylate (PMMA)film, a polycarbonate/polymethylmethacrylate (PC/PMMA) film, acombination thereof, or a greater than or equal to a two-layer stackthereof (see FIG. 14, in which the layers are indicated by 321 q and 322q). The plastic substrate 320 q may be, for example, about 50 μm toabout 100 μm thick.

The binder layer 320 p may reinforce (e.g., increase) a binding forcebetween the polymer layer 310 and the plastic substrate 320 q andinclude, for example, an acryl-based binder. The binder layer 320 p maybe, for example, about 5 μm to 10 μm thick. The binder layer 320 p maybe omitted.

The hard coating layer 320 r may be positioned on the surface of theplastic window 300 (e.g., on the surface of the plastic window 300 awayfrom the display panel 100) and may further improve surface hardness ofthe plastic window 300. The hard coating layer 320 r may include, forexample, an organic material, an inorganic material, or anorganic/inorganic composite compound. In one embodiment, the organicmaterial may include, for example, an acryl-based compound, anepoxy-based compound, or a combination thereof, the inorganic materialmay include, for example, silica, alumina, or a combination thereof, andthe organic/inorganic composite compound may include, for example,polysilsesquioxane, but these materials and compounds not limitedthereto. The hard coating layer 320 r may be a monolayer or multi-layerand, for example, about 50 μm to about 150 μm thick. The hard coatinglayer 320 r may be omitted.

The polymer layer 310 may be formed of an injection-moldable polymer.The injection moldable polymer may be, for example, selected from resinshaving a melt flow index (MFR) of greater than or equal to about 30 g/10min (with a reference to 300° C.), for example, about 30 g/10 min toabout 80 g/10 min (with a reference to 300° C.). The polymer layer 310may include, for example, polycarbonate (PC), apolycarbonate-polymethylmethacrylate (PC-PMMA) blend, a cycloolefinpolymer (COP), a copolymer thereof, a combination thereof, or greaterthan or equal to a two-layer stack thereof (see FIG. 14, in which thelayers are indicated by 311 and 312), but is not limited thereto.

The plastic window 300 may be less than or equal to about 1 mm thick.

The functional film 200 may include a touch screen panel (TSP) film, apolarizing film, or a combination thereof. The touch screen panel filmmay include, for example, a transparent electrode on a substrate, andthe polarizing film may have, for example, a structure of stacking aprotective layer, such as triacetyl cellulose (TAC), and a polarizer,such as polyvinylacetate (PVA).

The plastic window 300 and the functional film 200 may be adhered toeach other without an adhesive layer. For example, the lighttransmittance film 320 and the polymer layer 310 and also the functionalfilm 200 and the polymer layer 310 are injection-molded and adhered toeach other without an adhesive layer interposed therebetween.

The plastic window 300-functional film 200 assembly may be obtained byrespectively inserting the light transmittance film 320 and thefunctional film 200 into a mold in a dual-film insert manner, filling amolten polymer between the light transmittance film 320 and thefunctional film 200, and compressing them without an additional adhesionprocess.

The plastic window 300-functional film 200 assembly obtained in adual-film insert manner forms a closely adhered bond therebetweenwithout a separate adhesive layer and, thus, may prevent a thicknessincrease due to an adhesive layer and may simplify a manufacturingprocess due to omission of an adhesion process. In addition, the plasticwindow 300 may be prevented from being bent (e.g., permanently bent orcurved) by disposing the light transmittance film 320 and the functionalfilm 200 on both sides of the molten polymer during the injectionmolding and, thus, reducing or preventing distribution of asymmetricstress in a thickness direction and maintaining symmetric stress whenthe molten polymer is sharply cooled down during the injection molding.Accordingly, a display device may be prevented from being bent andreliability of a product may be increased.

The display panel 100 is positioned on one side of the plastic window300-functional film 200 assembly. The display panel 100 may be, forexample, a liquid crystal display panel or an organic light emittingdisplay panel.

The liquid crystal display panel may include first and second panelsfacing each other and a liquid crystal layer therebetween.

The first panel may include, for example, a thin film transistor on asubstrate and a first electric field-generating electrode coupled (e.g.,connected) thereto, and the second panel may include, for example, acolor filter and a second electric field-generating electrode on asubstrate. However, the present invention is not limited thereto, andthe color filter may be included in the first panel and/or the first andsecond electric field-generating electrodes may be positioned togetherin the first panel.

The liquid crystal layer may include a plurality of liquid crystalmolecules. The liquid crystal molecules may have positive or negativedielectric anisotropy. When the liquid crystal molecules have positivedielectric anisotropy, their long axes are almost parallel (e.g., aresubstantially parallel) to the surface of the first and second panels ina state of no electric field (e.g., when no electric field is appliedthereto). When an electric field is applied thereto, the liquid crystalmolecules are almost perpendicularly arranged (e.g., are substantiallyperpendicular) with respect to the surface of the first and seconddisplay panels. When the liquid crystal molecules have negativedielectric anisotropy, their long axes are almost perpendicular (e.g.,are substantially perpendicular) to the surface of the first and secondpanels in a state of no electric field. When an electric field isapplied thereto, the liquid crystal molecules are arranged almostparallel (e.g., are substantially parallel) to the surface of the firstand second panels.

The organic light emitting panel may include a base substrate, a lowerelectrode, an organic emission layer, an upper electrode, and anencapsulation substrate.

The base substrate may be made of glass or plastic.

One of a lower electrode and an upper electrode may be an anode and theother one may be a cathode. The anode is an electrode into which holesare injected and may be made of a transparent and conductive materialhaving a high work function and allow light to be emitted therethrough,for example, indium tin oxide (ITO) or indium zinc oxide (IZO). Thecathode is an electrode into which electrons are injected and may bemade of a conductive material having a low work function and having noinfluence on an organic material, for example, aluminum (Al), calcium(Ca), or barium (Ba).

The organic emission layer includes an organic material that emits lightwhen a voltage is applied to the lower and upper electrodes.

An auxiliary layer may be further included between the lower electrodeand the organic emission layer and between the upper electrode and theorganic emission layer. The auxiliary layer may include a holetransporting layer (HTL) to balance electrons and holes, a holeinjection layer (HIL), an electron injection layer (EIL), and/or anelectron transporting layer (ETL).

The encapsulation substrate may be made of glass, a metal, or a polymerand, thus, seals the lower electrode, organic emission layer, and upperelectrode to prevent moisture and/or oxygen from flowing therein.

The functional film 200 and the display panel 100 may be adhered byinterposing an adhesive layer 150 therebetween. The adhesive layer 150may include, for example, an optically clear adhesive (OCA).

Hereinafter, a method of manufacturing the display device is illustratedwith a reference to FIGS. 2 to 4.

FIGS. 2 to 4 are schematic views sequentially showing the method ofmanufacturing the display device according to one embodiment.

First, a light transmittance film 320 and a functional film 200 arerespectively prepared.

The light transmittance film 320 may be prepared by forming a binderlayer 320 p on one surface of a plastic substrate 320 q and a hardcoating layer 320 r on the other surface thereof. However, at least oneof the binder layer 320 p or the hard coating layer 320 r may beomitted.

The plastic substrate 320 q may be selected from, for example, apolyethyleneterephthalate (PET) film, a polycarbonate (PC) film, apolymethylmethacrylate (PMMA) film, apolycarbonate/polymethylmethacrylate (PC/PMMA) film, or a combinationthereof, the binder layer 320 p may include, for example, an acryl-basedbinder, and the hard coating layer 320 r may include, for example, anorganic material, an inorganic material, or an organic/inorganiccomposite compound.

The functional film 200 may be a touch screen panel film, a polarizingfilm, or a combination thereof. The touch screen panel film may beprepared by selectively forming a hard coating layer on a substrate,such as a PET substrate, and then forming a transparent electrodepattern, such as ITO, thereon. The polarizing film may be prepared byforming a protective layer, such as TAC, on one side or both sides of apolarizer, such as PVA, but is not limited thereto.

Subsequently, referring to FIG. 2, molds having a predetermined cavity10 and 20 are prepared, and the light transmittance film 320 and thefunctional film 200 are disposed (e.g., disposed at a predetermineddistance) between the molds 10 and 20. For example, the molds 10 and 20may have a plane-shaped groove, and the groove may have enough area(e.g., the groove may have sufficient width and/or depth) that the lighttransmittance film 320 and the functional film 200 may be insertedthereinto. One (e.g., either one) of the molds 10 and 20 has an inlet 30through which a molten polymer is inserted (e.g., injected), and themolten polymer may be supplied through the inlet 30.

Subsequently, referring to FIG. 3, the molds 10 and 20 are moved to becloser together to perform compression molding for thin injectionmolding.

Subsequently, referring to FIG. 4, the molten polymer 310 a is suppliedthrough the inlet 30 of the mold 10 and/or 20 and charged (e.g.,injected) between the light transmittance film 320 and the functionalfilm 200. The molten polymer 310 a may be, for example, selected fromresins having a melt flow index (MFR) of greater than or equal to about30 g/10 min (with a reference to 300° C.), for example, about 30 g/10min to about 80 g/10 min (with a reference to 300° C.). The moltenpolymer 310 a may include, for example, polycarbonate (PC), apolycarbonate-polymethylmethacrylate (PC-PMMA) blend, a cycloolefinpolymer (COP), a copolymer thereof, or a combination thereof, but is notlimited thereto.

Subsequently, the molten polymer 310 a is compressed and sharply cooleddown to form a polymer layer 310.

FIG. 5 is a schematic view showing a plastic window-functional filmassembly obtained in a dual-film insert manner according to oneembodiment.

In this embodiment, a plastic window 300-functional film 200 assemblyobtained by sequentially stacking the light transmittance film 320, thepolymer layer 310, and the functional film 200 in a dual-film insertmanner may be closely attached (e.g., closely adhered) without anadhesive layer.

FIG. 6 is a schematic view showing symmetric stress distribution of theplastic window-functional film assembly obtained in the dual-film insertmanner according to one embodiment.

Referring to FIG. 6, a plastic window obtained in a comparative (e.g.,general) film insert manner is bent (e.g., curved) toward one directiondue to asymmetric stress distribution when a molten polymer is sharplycooled down, while the plastic window-functional film assembly obtainedin the dual-film insert manner according to the embodiment symmetricallysupports the light transmittance film 320 and the functional film 200,maintains symmetric stress in a thickness direction, and may beprevented from being bent (e.g., permanently bent or curved) even thoughthe molten polymer is sharply cooled down. Accordingly, the preventionof the plastic window from being bent is improved and, thus, mayincrease reliability of a product.

Referring to FIGS. 10 to 13, high temperature reliability and hightemperature/humidity reliability evaluations of the plasticwindow-functional film assembly obtained in the dual-film insert mannerare illustrated.

In FIGS. 10 to 13, the plastic window-functional film assembly obtainedin the dual-film insert manner according to the embodiment includes atouch screen panel as a functional film.

FIG. 10 is a graph showing high temperature reliability evaluation ofthe plastic window-functional film assembly obtained in the dual-filminsert manner according to the embodiment, and FIG. 11 is a graphshowing high temperature reliability evaluation of the plastic windowobtained in a comparative film insert manner.

Referring to FIGS. 10 and 11, the plastic window-functional filmassembly obtained in the dual-film insert manner according to theembodiment is almost entirely straight (e.g., not bent or curved) whenallowed to stand at 85° C. (see FIG. 10), while the plastic windowobtained in the comparative film insert manner is largely bent or curvedwhen allowed to stand at 85° C. (see FIG. 11).

FIG. 12 is a graph showing high temperature/humidity reliabilityevaluation of the plastic window-functional film assembly obtained inthe dual-film insert manner according to the embodiment, while FIG. 13is a graph showing high temperature/humidity reliability evaluation ofthe plastic window obtained in the comparative film insert manner.

Referring to FIGS. 12 and 13, the plastic window-functional filmassembly obtained in the dual-film insert manner according to theembodiment is almost entirely straight (e.g., not bent or curved) at a85° C. temperature/85% humidity evaluation (see FIG. 12), while theplastic window obtained in the comparative film insert manner is largelybent at a 85° C. temperature/85% humidity evaluation (see FIG. 13).

The plastic window-functional film assembly is assembled with a displaypanel and manufactured into a display device.

Hereinafter, a method of manufacturing the display device according toanother embodiment is illustrated.

FIGS. 7 to 9 are schematic views sequentially showing a method ofmanufacturing the display device according to another embodiment.

According to the embodiment, a display panel 100 is adhered to afunctional film 200 before performing injection molding in a dual-filminsert manner, unlike the above embodiment.

First, a light transmittance film 320 and the functional film 200 arerespectively prepared.

The light transmittance film 320 may be prepared by forming a binderlayer 320 p on one surface of a plastic substrate 320 q and a hardcoating layer 320 r on the other surface thereof as described above.However, at least one of the binder layer 320 p or the hard coatinglayer 320 r may be omitted.

The functional film 200 may be prepared by preparing a touch screenpanel film, a polarizing film, or a combination thereof and attachingthe display panel 100 on one side of the touch screen panel film, thepolarizing film, or the combination thereof. The attachment of thedisplay panel 100 to the touch screen panel film, the polarizing film,or the combination thereof may be performed by using an adhesive agent.

Referring to FIG. 7, molds 10 and 20 having a predetermined cavity areprepared, and the functional film 200 having the display panel 100attached thereto and the light transmittance film 320 are disposed at aspace (e.g., a predetermined space) inside (e.g., between) the molds 10and 20. For example, the molds 10 and 20 may have a plane-shaped groove,and the groove may have enough area that the light transmittance film320 and the functional film 200, to which the display panel 100 isbound, may be inserted therein. At least one of the molds 10 and 20 mayhave an inlet 30 through which a molten polymer may be inserted, andthus, the molten polymer may be supplied through the inlet 30.

Referring to FIG. 8, the molds 10 and 20 are brought closer together andcompressed for thin film injection molding.

Referring to FIG. 9, the molten polymer 310 a is supplied through theinlet 30 of the molds 10 and/or 20 to fill the molten polymer 310 abetween the light transmittance film 320 and the functional film 200 towhich the display panel 100 is bound.

Subsequently, the molten polymer 310 a is compressed and sharply cooleddown to form a polymer layer 310.

While this disclosure has been described in connection with what ispresently considered to be practical example embodiments, it is to beunderstood that the invention is not limited to the disclosedembodiments, but is intended to cover various modifications andequivalent arrangements included within the spirit and scope of theappended claims and their equivalents.

What is claimed is:
 1. A method of manufacturing a display device, the method comprising: preparing a light transmittance film; preparing a functional film comprising a touch screen panel film, a polarizing film, or a combination thereof; placing the light transmittance film and the functional film in a mold; injecting a molten polymer between the light transmittance film and the functional film; and compressing the light transmittance film and the functional film to mold the polymer, wherein the polymer has a melt flow index (MFR) in a range of 30 g/10 min to 80 g/10 min with a reference to 300° C.
 2. The method of claim 1, wherein the preparing the light transmittance film comprises forming a hard coating layer on one surface of a plastic substrate.
 3. The method of claim 2, wherein the plastic substrate is selected from among a polyethyleneterephthalate (PET) film, a polycarbonate (PC) film, a polymethylmethacrylate (PMMA) film, a polycarbonate/polymethylmethacrylate (PC/PMMA) film, a combination thereof, or a two or more layer stack thereof.
 4. The method of claim 1, wherein the preparing the functional film comprises: preparing a touch screen panel film, a polarizing film, or a combination thereof; and attaching a display panel on one surface of the touch screen panel film, the polarizing film, or the combination thereof.
 5. The method of claim 1, wherein the polymer comprises polycarbonate (PC), a polycarbonate-polymethylmethacrylate (PC-PMMA) blend, a cycloolefin polymer (COP), a copolymer thereof, or a combination thereof. 